#!/usr/bin/perl
use strict;
use Tk;
use threads;
use threads::shared;

my $data_out:shared = '';
my $data_in:shared = '';
my $thread_die = 0;

#create the thread before you start any Tk so the
#thread dosn't get any Tk stuff copied in
my $wthr = threads->new( \&update_thread )->detach;

create_tk_window();

exit;

######################################################### 
#the non-Tk worker code 
sub update_thread {
    print "update_thread called...\n";
    while (1) {
          if($thread_die == 1){return}
          $data_in = 'thread-processing'.$data_out;
          sleep 1;
          }
END:
}
######################################################### 

sub create_tk_window {
  my $mw = MainWindow->new(
        -background => 'black',
        -foreground => 'yellow',
        -title      => "Thread Test"
    );
    $mw->geometry("600x400");
    $mw->minsize( 400, 400 );
    $mw->maxsize( 800, 800 );

  my $sent_text = $mw->Scrolled('Text',
        -height     => 10,
        -width      => 60,
        -background => 'black',
        -foreground => 'yellow'
    )->pack( -side => 'bottom', -anchor => 's', -pady => 2 );

  my $received_text = $mw->Scrolled(
        "Text",
        -height     => 10,
        -width      => 60,
        -background => 'white',
        -foreground => 'black',
    )->pack();

  my $repeater;

  $mw->Button(-text=> 'Exit',
              -command => sub{
                $thread_die = 1;
                $repeater->cancel;
                $mw->withdraw;
                kill 9, $$;
            })->pack;

  $repeater = $mw->repeat(1000, sub{
    $data_out++;
    $sent_text->insert( 'end', "Sent $data_out\n" );
    $sent_text->see('end');

    $received_text->insert( 'end', "Received $data_in\n" );
    $received_text->see('end');
    });
MainLoop;
}